org.xmlBlaster.util.queue.jdbc
Class JdbcQueue

java.lang.Object
  org.xmlBlaster.util.queue.jdbc.JdbcQueue

All Implemented Interfaces:

org.xmlBlaster.engine.msgstore.I_Map, I_Plugin, I_Queue, I_Storage, I_StoragePlugin, I_StorageProblemNotifier

public final class JdbcQueue
extends java.lang.Object
implements I_Queue, I_StoragePlugin, org.xmlBlaster.engine.msgstore.I_Map

Persistence queue implementation on a DB based on JDBC.

Loaded via xmlBlaster.properties, there are three implementation (the first, using a table per topic, was dropped long ago).

org.xmlBlaster.util.queue.jdbc.JdbcQueueCommonTablePlugin
was the operational variant up to v1.6.2+ (2008-10) using one XB_ENTRIES table

org.xmlBlaster.util.queue.jdbc.JdbcQueue
is the new implementation since v1.6.3 using three tables XBSTORE, XBREF, XBMEAT

Example:

 JdbcStorage[postgres]=org.xmlBlaster.util.queue.jdbc.JdbcQueue,\
                      url=jdbc:postgresql://localhost:5432/test,\
                      user=postgres,\
                      password=,\
                      connectionPoolSize=1,\
                      connectionBusyTimeout=90000,\
                      maxWaitingThreads=300,\
                      tableNamePrefix=XB_,\
                      entriesTableName=ENTRIES,\
                      dbAdmin=true
 

Author:

michele@laghi.eu, xmlBlaster@marcelruff.info

See Also:

The queue.jdbc.commontable requirement, JdbcQueueCommonTablePlugin

Field Summary

Fields inherited from interface org.xmlBlaster.util.queue.I_Queue

IGNORE_PUT_INTERCEPTOR, USE_PUT_INTERCEPTOR

Constructor Summary

JdbcQueue()

Method Summary

void	addPutListener(I_QueuePutListener l) Register a listener which wants to be informed on put() events.
void	addStorageSizeListener(I_StorageSizeListener listener) Adds a storage size listener to the storage.
org.xmlBlaster.engine.msgstore.I_MapEntry	change(org.xmlBlaster.engine.msgstore.I_MapEntry entry, org.xmlBlaster.engine.msgstore.I_ChangeCallback callback)
org.xmlBlaster.engine.msgstore.I_MapEntry	change(long uniqueId, org.xmlBlaster.engine.msgstore.I_ChangeCallback callback) This method is threadsafe because it makes a lookup for the updated entry within the synchronization point.
long	clear() Clears everything and removes the queue (i.e.
void	destroy() Cleans up the current queue (it deletes all the entries and frees the table used and cleans up all tables in the database).
long	embeddedObjectsToXml(java.io.OutputStream out, java.util.Properties props) Note: Is currently implemented assuming I_MapEntry and NOT I_QueueEntry (but I_Queue offers this method which is wrong)
long	embeddedQueueObjectsToXml(java.io.OutputStream out, java.util.Properties props) NOTE: rename from embeddedObjectsToXml to embeddedQueueObjectsToXml as it used the map lookup and lost priority info Dump all entries of this queue to the given output stream.
org.xmlBlaster.engine.msgstore.I_MapEntry	get(long uniqueId) Lookup entry without removing.
org.xmlBlaster.engine.msgstore.I_MapEntry[]	getAll(I_EntryFilter entryFilter) Retrieve all entries in the storage, please take care on memory consumption.
java.util.ArrayList	getEntries(I_EntryFilter entryFilter) Gets a copy of the entries (e.g the messages) in the queue.
long[]	getEntryReferences() Gets the references of the entries in the queue.
protected XBDatabaseAccessor	getFactory(PluginInfo plugInfo) Returns the factory for a specific queue.
PluginInfo	getInfo() Enforced by I_StoragePlugin
long	getMaxNumOfBytes() returns the capacity (maximum bytes) for this queue
long	getMaxNumOfEntries() Returns the maximum number of elements for this queue
long	getNumOfBytes() It returns the size of the queue.
long	getNumOfEntries() It returns the size of the queue.
long	getNumOfPersistentBytes() It returns the number of persistent entries in the queue.
long	getNumOfPersistentEntries() It returns the number of persistent entries in the queue.
java.lang.Object	getProperties() Access the current queue configuration
StorageId	getStorageId() Returns the unique ID of this queue
I_StorageSizeListener[]	getStorageSizeListeners()
java.lang.String	getType() Enforced by I_Plugin
java.lang.String	getVersion() Enforced by I_Plugin
boolean	hasStorageSizeListener(I_StorageSizeListener listener) Checks wether the specified listener is registered.
void	init(Global glob, PluginInfo pluginInfo) Enforced by I_Plugin
void	initialize(StorageId uniqueQueueId, java.lang.Object userData) Is called after the instance is created.
boolean	isNotifiedAboutAddOrRemove() Defaults to false.
boolean	isShutdown() Performs what has to be done when the Map Plugin shuts down.
boolean	isTransient()
I_QueueEntry	peek() Returns the first element in the queue but does not remove it from that queue (leaves it untouched).
java.util.ArrayList	peek(int numEntries, long numBytes) Returns maximum the first num element in the queue but does not remove it from that queue (leaves it untouched).
java.util.ArrayList	peekLowest(int numEntries, long numBytes, I_QueueEntry limitEntry, boolean leaveOne) Same as takeLowest but it does not remove the entries.
java.util.ArrayList	peekSamePriority(int numEntries, long numBytes) Returns maximum the first num element in the queue of highest priority but does not remove it from that queue (leaves it untouched).
java.util.ArrayList	peekStartAt(int numOfEntries, long numOfBytes, I_QueueEntry firstEntryExlusive) Returns maximum the first num element in the queue but does not remove it from that queue (leaves it untouched).
java.util.ArrayList	peekWithLimitEntry(I_QueueEntry limitEntry) Deprecated.
java.util.ArrayList	peekWithPriority(int numEntries, long numBytes, int minPriority, int maxPriority) Returns maximum given number of entries from the queue (none blocking).
int	put(org.xmlBlaster.engine.msgstore.I_MapEntry mapEntry) Adds one entry and automatically increments the reference counter.
void	put(I_QueueEntry[] queueEntries, boolean ignorePutInterceptor) Puts one queue entry on top of the queue.
void	put(I_QueueEntry queueEntry, boolean ignorePutInterceptor) Puts one queue entry on top of the queue.
boolean	registerStorageProblemListener(I_StorageProblemListener listener) registers a new listener to be notified.
int	remove() Removes the first element in the queue This method does not block.
int	remove(org.xmlBlaster.engine.msgstore.I_MapEntry mapEntry)
int	remove(long uniqueId) This method is always invoked with the I_Map interface
long	removeHead(I_QueueEntry toEntry) removes the head of the queue until (but not included) the entry specified as the argument.
long	removeNum(long numEntries) Removes max numOfEntries messages.
org.xmlBlaster.engine.msgstore.I_MapEntry	removeOldest() Remove the oldest entry.
void	removePutListener(I_QueuePutListener l) Remove the listener which wanted to be informed on put() events.
int	removeRandom(I_Entry entry) Removes the given entry.
boolean[]	removeRandom(I_Entry[] queueEntries) Removes the given entries.
int	removeRandom(long dataId) Removes the given entry.
boolean[]	removeRandom(long[] dataIdArray) Removes the given entries.
void	removeStorageSizeListener(I_StorageSizeListener listener) Removes the specified listener from the queue.
long	removeWithLimitEntry(I_QueueEntry limitEntry, boolean inclusive) It removes the entries which are higher than the entry specified in the argument list.
long	removeWithPriority(long numEntries, long numBytes, int minPriority, int maxPriority) Removes max numOfEntries messages (or less depending on the numOfBytes).
void	setNotifiedAboutAddOrRemove(boolean notify)
void	setProperties(java.lang.Object userData) Allows to overwrite properties which where passed on initialize() The properties which support hot configuration are depending on the used implementation
void	shutdown() Shutdown the implementation, sync with data store
I_QueueEntry	take() Currently not supported by I_Queue.
java.util.ArrayList	take(int numEntries, long numBytes) Currently not supported by I_Queue.
java.util.ArrayList	takeLowest(int numEntries, long numBytes, I_QueueEntry limitEntry, boolean leaveOne) Takes entries from the back of the queue.
java.util.ArrayList	takeWithPriority(int numOfEntries, long numOfBytes, int minPriority, int maxPriority) Takes given number of entries out of the queue.
java.lang.String	toXml(java.lang.String extraOffset) Dump state to XML string.
boolean	unRegisterStorageProblemListener(I_StorageProblemListener listener) unregisters a listener.
int	update(I_QueueEntry queueEntry) Updates the given message queue entry with a new value.
void	updateCounters(org.xmlBlaster.engine.msgstore.I_MapEntry entry)
java.lang.String	usage()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JdbcQueue

public JdbcQueue()

Method Detail

isTransient

public boolean isTransient()

Specified by:

isTransient in interface I_Storage

Returns:

true for RAM based queue, false for other types like CACHE and JDBC queues

getFactory

protected XBDatabaseAccessor getFactory(PluginInfo plugInfo)
                                 throws XmlBlasterException

Returns the factory for a specific queue. It strips the queueId to find out to which manager it belongs. If such a manager does not exist yet, it is created and initialized. A queueId must be of the kind: cb:some/id/or/someother where the important requirement here is that it contains a ':' character. text on the left side of the separator (in this case 'cb') tells which kind of queue it is: for example a callback queue (cb) or a client queue.

Throws:

XmlBlasterException

initialize

public void initialize(StorageId uniqueQueueId,
                       java.lang.Object userData)
                throws XmlBlasterException

Is called after the instance is created.

Specified by:

initialize in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

initialize in interface I_Queue

Parameters:

uniqueQueueId - A unique name, allowing to create a unique name for a persistent store (e.g. file name)

userData - For example a Properties object or a String[] args object passing the configuration data

Throws:

XmlBlasterException

See Also:

I_Queue.initialize(StorageId, Object)

setProperties

public void setProperties(java.lang.Object userData)
                   throws XmlBlasterException

Description copied from interface: org.xmlBlaster.engine.msgstore.I_Map

Allows to overwrite properties which where passed on initialize() The properties which support hot configuration are depending on the used implementation

Specified by:

setProperties in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

setProperties in interface I_Queue

Throws:

XmlBlasterException

See Also:

I_Queue.setProperties(Object)

getProperties

public java.lang.Object getProperties()

Access the current queue configuration

Specified by:

getProperties in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

getProperties in interface I_Queue

setNotifiedAboutAddOrRemove

public void setNotifiedAboutAddOrRemove(boolean notify)

Specified by:

setNotifiedAboutAddOrRemove in interface I_Queue

isNotifiedAboutAddOrRemove

public boolean isNotifiedAboutAddOrRemove()

Description copied from interface: I_Queue

Defaults to false.

Specified by:

isNotifiedAboutAddOrRemove in interface I_Queue

Returns:

true The I_QueueEntry.addedToQueue() and removedFromQueue() are invoked
false The entries are not informed

addPutListener

public void addPutListener(I_QueuePutListener l)

Description copied from interface: I_Queue

Register a listener which wants to be informed on put() events.

Only one listener is currently supported.

Specified by:

addPutListener in interface I_Queue

See Also:

I_Queue.addPutListener(I_QueuePutListener)

removePutListener

public void removePutListener(I_QueuePutListener l)

Description copied from interface: I_Queue

Remove the listener which wanted to be informed on put() events.

The currently registered listener is removed. If no listener is registered, this call is silently ignored

Specified by:

removePutListener in interface I_Queue

See Also:

I_Queue.removePutListener(I_QueuePutListener)

getEntryReferences

public long[] getEntryReferences()
                          throws XmlBlasterException

Gets the references of the entries in the queue. Note that the data which is referenced here may be changed by other threads.

Specified by:

getEntryReferences in interface I_Queue

Returns:

Array with reference numbers

Throws:

XmlBlasterException

getEntries

public java.util.ArrayList getEntries(I_EntryFilter entryFilter)
                               throws XmlBlasterException

Description copied from interface: I_Queue

Gets a copy of the entries (e.g the messages) in the queue. If the queue is modified, this copy will not be affected. This method is useful for client browsing, the entries are not removed

Specified by:

getEntries in interface I_Queue

Parameters:

entryFilter - if not null the you can control which entries to return with the callback entryFilter.intercept(I_Entry).

Returns:

The found entries

Throws:

XmlBlasterException

See Also:

I_Queue.getEntries(I_EntryFilter)

put

public void put(I_QueueEntry queueEntry,
                boolean ignorePutInterceptor)
         throws XmlBlasterException

Description copied from interface: I_Queue

Puts one queue entry on top of the queue. See the other put() for a detailed description.

Specified by:

put in interface I_Queue

ignorePutInterceptor - if set to 'IGNORE_PUT_INTERCEPTOR=true' the put will not inform the QueuePutListener that a put occurred.

Throws:

XmlBlasterException - in case an error occurs. Possible causes of error can be a communication exception of the underlying implementation (jdbc, file system etc).

See Also:

I_Queue.put(I_QueueEntry, boolean)

put

public void put(I_QueueEntry[] queueEntries,
                boolean ignorePutInterceptor)
         throws XmlBlasterException

Description copied from interface: I_Queue

Puts one queue entry on top of the queue. It does not wait. If the queue is ALREADY full at the time of the invocation, it will throw an exception. Full means here that the maximum number of entries OR the maximum size in bytes has been exceeded. This means that the queue can be overloaded once.

The implementation must assure that identical entries which are put twice are only once in the store. The behavior if the new entry overwrites the old entry is undefined.

Specified by:

put in interface I_Queue

ignorePutInterceptor - if set to 'IGNORE_PUT_INTERCEPTOR=true' the put will not inform the QueuePutListener that a put occurred.

Throws:

XmlBlasterException - in case an error occurs. Possible causes of error can be a communication exception of the underlying implementation (jdbc, file system etc).

See Also:

I_Queue.put(I_QueueEntry[], boolean)

getStorageId

public StorageId getStorageId()

Returns the unique ID of this queue

Specified by:

getStorageId in interface I_Storage

Returns:

For example "history_heronhello"

take

public I_QueueEntry take()
                  throws XmlBlasterException

Currently not supported by I_Queue.

Throws:

XmlBlasterException

takeWithPriority

public java.util.ArrayList takeWithPriority(int numOfEntries,
                                            long numOfBytes,
                                            int minPriority,
                                            int maxPriority)
                                     throws XmlBlasterException

Description copied from interface: I_Queue

Takes given number of entries out of the queue. The ordering is first priority and secondly timestamp. This method blocks until at least one entry is found

Specified by:

takeWithPriority in interface I_Queue

Parameters:

numOfEntries - Take numOfEntries entries, if -1 take all entries currently found

numOfBytes - so many entries are returned as not to exceed the amount specified. If the first entry is bigger than this amount, it is returned anyway.

minPriority - The lower priority (inclusive), usually 0 lowest, 9 highest

maxPriority - The higher priority (inclusive), usually 0 lowest, 9 highest

Returns:

list with I_QueueEntry, the least elements with respect to the given ordering, or size()==0

Throws:

XmlBlasterException - in case the underlying implementation gets an exception while retrieving the element.

See Also:

I_Queue.takeWithPriority(int,long,int,int)

take

public java.util.ArrayList take(int numEntries,
                                long numBytes)
                         throws XmlBlasterException

Currently not supported by I_Queue.

Throws:

XmlBlasterException

takeLowest

public java.util.ArrayList takeLowest(int numEntries,
                                      long numBytes,
                                      I_QueueEntry limitEntry,
                                      boolean leaveOne)
                               throws XmlBlasterException

Description copied from interface: I_Queue

Takes entries from the back of the queue. It takes so many entries as the LESS restrictive of the limits specified in the argument list. If you invoke this method as: takeLowest(10, 50000L, someEntry); It will take either 10 entries or as much entries which together do not exceed 50 kB (all entries together) whichever is higher. Note that numOfEntries is exclusive. If there is no entry of lower order (lower priority and higher uniqueId) than the one specified, an empty array list is returned. A further restriction is the following: if 'leaveOne' is 'true', then at least one entry must be left on the queue. A little example: suppose the size of every entry is 100 bytes and you invoke the following: takeLowest(3, 750, null, false); then it will give back 8 entries because: numEntries would give back 3 entries. 750 bytes / 100 bytes/entry gives 7.5 entries so it would round it up to 8. Since it gives back the less restrictive it will give back 8 entries.

Specified by:

takeLowest in interface I_Queue

Parameters:

numEntries - inclusive, zero up to numOfEntries, if -1 up to the whole queue

numBytes - inclusive, and minimum one is returned (but not if limitEntry suppress it)

leaveOne - Usually set to false. (true for cache queue to never flush transient queue totally)

Returns:

the list containing all 'I_QueueEntry' entries which fit into the constrains, never null.

Throws:

XmlBlasterException

See Also:

I_Queue.takeLowest(int, long, I_QueueEntry, boolean)

peekLowest

public java.util.ArrayList peekLowest(int numEntries,
                                      long numBytes,
                                      I_QueueEntry limitEntry,
                                      boolean leaveOne)
                               throws XmlBlasterException

Description copied from interface: I_Queue

Same as takeLowest but it does not remove the entries.

Specified by:

peekLowest in interface I_Queue

Throws:

XmlBlasterException

See Also:

I_Queue.peekLowest(int, long, I_QueueEntry, boolean)

peek

public I_QueueEntry peek()
                  throws XmlBlasterException

Description copied from interface: I_Queue

Returns the first element in the queue but does not remove it from that queue (leaves it untouched). This method does not block.

Specified by:

peek in interface I_Queue

Returns:

I_QueueEntry the least element with respect to the given ordering or null if the queue is empty.

Throws:

XmlBlasterException - if the underlying implementation gets an exception.

See Also:

I_Queue.peek()

peek

public java.util.ArrayList peek(int numEntries,
                                long numBytes)
                         throws XmlBlasterException

Description copied from interface: I_Queue

Returns maximum the first num element in the queue but does not remove it from that queue (leaves it untouched). This method does not block.

Specified by:

peek in interface I_Queue

Parameters:

numEntries - Access num entries, if -1 access all entries currently found

numBytes - is the maximum size in bytes of the array to return, -1 is unlimited .

Returns:

list with I_QueueEntry, the least elements with respect to the given ordering, or size()==0

Throws:

XmlBlasterException - if the underlying implementation gets an exception.

See Also:

I_Queue.peek(int,long)

peekStartAt

public java.util.ArrayList peekStartAt(int numOfEntries,
                                       long numOfBytes,
                                       I_QueueEntry firstEntryExlusive)
                                throws XmlBlasterException

Description copied from interface: I_Queue

Returns maximum the first num element in the queue but does not remove it from that queue (leaves it untouched). This method does not block.

Specified by:

peekStartAt in interface I_Queue

Parameters:

numOfEntries - Access num entries, if -1 access all entries currently found

numOfBytes - is the maximum size in bytes of the array to return, -1 is unlimited .

Returns:

list with I_QueueEntry, the least elements with respect to the given ordering, or size()==0

Throws:

XmlBlasterException - if the underlying implementation gets an exception.

See Also:

I_Queue.peekStartAt(int,long,I_QueueEntry)

peekSamePriority

public java.util.ArrayList peekSamePriority(int numEntries,
                                            long numBytes)
                                     throws XmlBlasterException

Description copied from interface: I_Queue

Returns maximum the first num element in the queue of highest priority but does not remove it from that queue (leaves it untouched). This method does not block.

Specified by:

peekSamePriority in interface I_Queue

Parameters:

numEntries - Access num entries, if -1 access all entries currently found

numBytes - so many entries are returned as not to exceed the amount specified. If the first entry is bigger than this amount, it is returned anyway. -1 is unlimited.

Returns:

list with I_QueueEntry, the least elements with respect to the given ordering, or size()==0

Throws:

XmlBlasterException - if the underlying implementation gets an exception.

See Also:

I_Queue.peekSamePriority(int, long)

peekWithPriority

public java.util.ArrayList peekWithPriority(int numEntries,
                                            long numBytes,
                                            int minPriority,
                                            int maxPriority)
                                     throws XmlBlasterException

Description copied from interface: I_Queue

Returns maximum given number of entries from the queue (none blocking).

Specified by:

peekWithPriority in interface I_Queue

Parameters:

numEntries - Access num entries, if -1 take all entries currently found

numBytes - so many entries are returned as not to exceed the amount specified. If the first entry is bigger than this amount, it is returned anyway.

minPriority - The lower priority (inclusive), usually 0 lowest, 9 highest, <0 is not allowed

maxPriority - The higher priority (inclusive), usually 0 lowest, 9 highest, <0 is not allowed

Returns:

list with I_QueueEntry, the least elements with respect to the given ordering, or size()==0

Throws:

XmlBlasterException - in case the underlying implementation gets an exception while retrieving the element.

See Also:

I_Queue.peekWithPriority(int, long, int, int)

peekWithLimitEntry

public java.util.ArrayList peekWithLimitEntry(I_QueueEntry limitEntry)
                                       throws XmlBlasterException

Deprecated.

Description copied from interface: I_Queue

It returns the entries which are higher than the entry specified in the argument list.

Specified by:

peekWithLimitEntry in interface I_Queue

Parameters:

limitEntry - the entry which limits the peek. Only entries of higher order, i.e. entries having a higher priority, or same priority and lower uniqueId are returned. If entryLimit is null or no entries are higher than entryLimit, an empty list is returned. Note: The limitEntry does not need to be in the queue.

Throws:

XmlBlasterException

See Also:

I_Queue.peekWithLimitEntry(I_QueueEntry)

removeWithLimitEntry

public long removeWithLimitEntry(I_QueueEntry limitEntry,
                                 boolean inclusive)
                          throws XmlBlasterException

Description copied from interface: I_Queue

It removes the entries which are higher than the entry specified in the argument list.

Specified by:

removeWithLimitEntry in interface I_Queue

Parameters:

limitEntry - the entry which limits the remove. Only entries of higher order, i.e. entries having a higher priority, or same priority and lower uniqueId are deleted. If entryLimit is null or no entries are higher than entryLimit, an empty list is returned.

inclusive - if 'true', then also the entry specified will be removed (if it exists). If false the remove is exclusive, i.e. the specified entry is left in the queue. Note: The limitEntry does not need to be in the queue.

Throws:

XmlBlasterException

See Also:

I_Queue.removeWithLimitEntry(I_QueueEntry, boolean)

remove

public int remove()
           throws XmlBlasterException

Removes the first element in the queue This method does not block.

Specified by:

remove in interface I_Queue

Returns:

Number of messages erased (0 or 1)

Throws:

XmlBlasterException - if the underlying implementation gets an exception.

removeNum

public long removeNum(long numEntries)
               throws XmlBlasterException

Removes max numOfEntries messages. This method does not block.

Specified by:

removeNum in interface I_Queue

Parameters:

numEntries - Erase num entries or less if less entries are available, -1 erases everything

Returns:

Number of entries erased

Throws:

XmlBlasterException - if the underlying implementation gets an exception.

removeRandom

public int removeRandom(long dataId)
                 throws XmlBlasterException

Removes the given entry.

Parameters:

dataId - the unique id. It must be unique within the storage area of the implementing queue. In other words, if the underlying implementation is on RAM, then the storage area is the JVM, that is the queue must be unique in the same JVM. If the queue is a jdbc, the dataId is unique in the DB used.

Throws:

XmlBlasterException

removeRandom

public boolean[] removeRandom(long[] dataIdArray)
                       throws XmlBlasterException

Removes the given entries.

Parameters:

msgQueueEntry - the entry to erase.

Throws:

XmlBlasterException

removeRandom

public int removeRandom(I_Entry entry)
                 throws XmlBlasterException

Description copied from interface: I_Queue

Removes the given entry.

Specified by:

removeRandom in interface I_Queue

Parameters:

entry - The entry to erase.

Returns:

the number of elements erased.

Throws:

XmlBlasterException

See Also:

I_Queue.removeRandom(I_Entry)

removeRandom

public boolean[] removeRandom(I_Entry[] queueEntries)
                       throws XmlBlasterException

Description copied from interface: I_Queue

Removes the given entries.

Specified by:

removeRandom in interface I_Queue

Parameters:

queueEntries - the entries to erase.

Returns:

a boolean array of the same size as the queueEntries array. If an entry is true it means it could be removed, if false it means it could not be removed (probably already removed)

Throws:

XmlBlasterException

See Also:

I_Queue.removeRandom(I_Entry[])

removeWithPriority

public long removeWithPriority(long numEntries,
                               long numBytes,
                               int minPriority,
                               int maxPriority)
                        throws XmlBlasterException

Description copied from interface: I_Queue

Removes max numOfEntries messages (or less depending on the numOfBytes). This method does not block.

Specified by:

removeWithPriority in interface I_Queue

Parameters:

numEntries - Erase num entries or less if less entries are available, -1 erases everything

numBytes - so many entries are returned as not to exceed the amout specified. If the first entry is bigger than this amount, it is returned anyway.

minPriority - The lower priority (inclusive), usually 0 lowest, 9 highest

maxPriority - The higher priority (inclusive), usually 0 lowest, 9 highest

Returns:

Number of entries erased

Throws:

XmlBlasterException - in case the underlying implementation gets an exception while retrieving the element.

See Also:

I_Queue.removeWithPriority(long, long, int, int)

getNumOfEntries

public long getNumOfEntries()

It returns the size of the queue. Note that this call will return the size stored in cache. In case this value is -1L (which means a previous attempt to read from the DB failed) it will synchronize against the DB by making a call to the DB. If that fails it will return -1L.

Specified by:

getNumOfEntries in interface I_Storage

Returns:

int the number of elements

See Also:

I_Storage.getNumOfEntries()

getNumOfPersistentEntries

public long getNumOfPersistentEntries()

It returns the number of persistent entries in the queue. In case this value is -1L (which means a previous attempt to read from the DB failed) it will synchronize against the DB by making a call to the DB. If that fails it will return -1L.

Specified by:

getNumOfPersistentEntries in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

getNumOfPersistentEntries in interface I_Queue

Returns:

int the number of elements currently in the queue

See Also:

I_Queue.getNumOfPersistentEntries()

getMaxNumOfEntries

public long getMaxNumOfEntries()

Description copied from interface: I_Storage

Returns the maximum number of elements for this queue

Specified by:

getMaxNumOfEntries in interface I_Storage

Returns:

The maximum number of elements in the queue

See Also:

I_Storage.getMaxNumOfEntries()

getNumOfBytes

public long getNumOfBytes()

It returns the size of the queue. Note that this call will return the size stored in cache. In case this value is -1L (which means a previous attempt to read from the DB failed) it will synchronize against the DB by making a call to the DB. If that fails it will return -1L.

Specified by:

getNumOfBytes in interface I_Storage

Returns:

The number of elements currently in the queue

See Also:

I_Storage.getNumOfBytes()

getNumOfPersistentBytes

public long getNumOfPersistentBytes()

It returns the number of persistent entries in the queue. In case this value is -1L (which means a previous attempt to read from the DB failed) it will synchronize against the DB by making a call to the DB. If that fails it will return -1L.

Specified by:

getNumOfPersistentBytes in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

getNumOfPersistentBytes in interface I_Queue

Returns:

int the number of elements currently in the queue

See Also:

I_Queue.getNumOfPersistentBytes()

getMaxNumOfBytes

public long getMaxNumOfBytes()

Description copied from interface: org.xmlBlaster.engine.msgstore.I_Map

returns the capacity (maximum bytes) for this queue

Specified by:

getMaxNumOfBytes in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

getMaxNumOfBytes in interface I_Queue

Returns:

int the maximum number of elements in the queue

See Also:

I_Queue.getMaxNumOfBytes()

update

public int update(I_QueueEntry queueEntry)
           throws XmlBlasterException

Updates the given message queue entry with a new value. Note that this can be used if an entry with the unique id already exists. ?? Does this really make sense here since we need to store history ?? ?? Should we define a switch which can deactivate storage of history ??

Throws:

XmlBlasterException

clear

public long clear()

Clears everything and removes the queue (i.e. frees the associated table)

Specified by:

clear in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

clear in interface I_Queue

Returns:

Number of entries removed

removeHead

public long removeHead(I_QueueEntry toEntry)
                throws XmlBlasterException

Description copied from interface: I_Queue

removes the head of the queue until (but not included) the entry specified as the argument.

Specified by:

removeHead in interface I_Queue

Parameters:

toEntry - the entry until to remove.

Returns:

long the number of entries deleted.

Throws:

XmlBlasterException

See Also:

I_Queue.removeHead(I_QueueEntry)

shutdown

public void shutdown()

Shutdown the implementation, sync with data store

Specified by:

shutdown in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

shutdown in interface I_Plugin

Specified by:

shutdown in interface I_Queue

isShutdown

public boolean isShutdown()

Description copied from interface: I_Storage

Performs what has to be done when the Map Plugin shuts down.

Specified by:

isShutdown in interface I_Storage

usage

public java.lang.String usage()

Specified by:

usage in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

usage in interface I_Queue

Returns:

a human readable usage help string

toXml

public final java.lang.String toXml(java.lang.String extraOffset)

Description copied from interface: I_Queue

Dump state to XML string.

Specified by:

toXml in interface org.xmlBlaster.engine.msgstore.I_Map

Specified by:

toXml in interface I_Queue

Parameters:

extraOffset - Indent the dump with given ASCII blanks

Returns:

Internal state as an XML ASCII string

init

public void init(Global glob,
                 PluginInfo pluginInfo)

Enforced by I_Plugin

Specified by:

init in interface I_Plugin

See Also:

I_Plugin.init(org.xmlBlaster.util.Global, PluginInfo)

getType

public java.lang.String getType()

Enforced by I_Plugin

Specified by:

getType in interface I_Plugin

Returns:

"JDBC"

getVersion

public java.lang.String getVersion()

Enforced by I_Plugin

Specified by:

getVersion in interface I_Plugin

Returns:

"1.0"

getInfo

public PluginInfo getInfo()

Enforced by I_StoragePlugin

Specified by:

getInfo in interface I_StoragePlugin

Returns:

the pluginInfo object.

destroy

public void destroy()
             throws XmlBlasterException

Cleans up the current queue (it deletes all the entries and frees the table used and cleans up all tables in the database). This method should never be called, only for testing purposes or to clean up the entire database.

Specified by:

destroy in interface org.xmlBlaster.engine.msgstore.I_Map

Throws:

XmlBlasterException

get

public org.xmlBlaster.engine.msgstore.I_MapEntry get(long uniqueId)
                                              throws XmlBlasterException

Description copied from interface: org.xmlBlaster.engine.msgstore.I_Map

Lookup entry without removing.

Specified by:

get in interface org.xmlBlaster.engine.msgstore.I_Map

Returns:

null if not found

Throws:

XmlBlasterException

getAll

public org.xmlBlaster.engine.msgstore.I_MapEntry[] getAll(I_EntryFilter entryFilter)
                                                   throws XmlBlasterException

Description copied from interface: org.xmlBlaster.engine.msgstore.I_Map

Retrieve all entries in the storage, please take care on memory consumption.

Specified by:

getAll in interface org.xmlBlaster.engine.msgstore.I_Map

Parameters:

entryFilter - null to get everything. If specified you can filter by this callback the wanted entries.

Returns:

A current snapshot of all entries

Throws:

XmlBlasterException

See Also:

I_Map#getAll()

put

public int put(org.xmlBlaster.engine.msgstore.I_MapEntry mapEntry)
        throws XmlBlasterException

Description copied from interface: org.xmlBlaster.engine.msgstore.I_Map

Adds one entry and automatically increments the reference counter. Note: If an entry existed already (0 is returned), it is NOT updated in storage

Specified by:

put in interface org.xmlBlaster.engine.msgstore.I_Map

Returns:

Number of new entries added: 0 if entry existed, 1 if new entry added

Throws:

XmlBlasterException - in case an error occurs. Possible causes of error can be a communication exception of the underlying implementation (jdbc, file system etc).

See Also:

I_Map.put(I_MapEntry)

remove

public int remove(org.xmlBlaster.engine.msgstore.I_MapEntry mapEntry)
           throws XmlBlasterException

Specified by:

remove in interface org.xmlBlaster.engine.msgstore.I_Map

Returns:

the number of elements erased.

Throws:

XmlBlasterException

remove

public int remove(long uniqueId)
           throws XmlBlasterException

This method is always invoked with the I_Map interface

Specified by:

remove in interface org.xmlBlaster.engine.msgstore.I_Map

Returns:

the number of elements erased.

Throws:

XmlBlasterException

removeOldest

public org.xmlBlaster.engine.msgstore.I_MapEntry removeOldest()
                                                       throws XmlBlasterException

Description copied from interface: org.xmlBlaster.engine.msgstore.I_Map

Remove the oldest entry. 'Oldest' is defined in the context of the implementation to support an efficient cache, typically it is the LRU (last recent used) entry.

Specified by:

removeOldest in interface org.xmlBlaster.engine.msgstore.I_Map

Returns:

the removed entry

Throws:

XmlBlasterException

See Also:

I_Map.removeOldest()

registerStorageProblemListener

public boolean registerStorageProblemListener(I_StorageProblemListener listener)

Description copied from interface: I_StorageProblemNotifier

registers a new listener to be notified. If the registration was not done (for example if the implementation only allows one listener and there is already one), then a 'false' is returned, otherwise 'true' is returned.

Specified by:

registerStorageProblemListener in interface I_StorageProblemNotifier

See Also:

I_StorageProblemNotifier.registerStorageProblemListener(I_StorageProblemListener)

unRegisterStorageProblemListener

public boolean unRegisterStorageProblemListener(I_StorageProblemListener listener)

Description copied from interface: I_StorageProblemNotifier

unregisters a listener. If there is no such listener 'false' is returned, otherwise 'true' is returned.

Specified by:

unRegisterStorageProblemListener in interface I_StorageProblemNotifier

See Also:

I_StorageProblemNotifier.unRegisterStorageProblemListener(I_StorageProblemListener)

change

public org.xmlBlaster.engine.msgstore.I_MapEntry change(org.xmlBlaster.engine.msgstore.I_MapEntry entry,
                                                        org.xmlBlaster.engine.msgstore.I_ChangeCallback callback)
                                                 throws XmlBlasterException

Specified by:

change in interface org.xmlBlaster.engine.msgstore.I_Map

Parameters:

entry - the entry to change. This is the old entry, i.e. the entry on which the modification has to take place by callback. Or it is the new entry and you can pass null for callback. IMPORTANT: This method is not threadsafe since it does not make a lookup to get the actual entry. The specified entry could be a dirty read, in which case the current entry would be overwritten with this dirty value. If you want to work threadsafe you should invoke change(long, callback). That method makes a lookup within the same synchronization point.

callback - the object on which the callback method 'changeEntry' is invoked. The modification of the object is done in that method. If you pass null, then the changeEntry is not invoked and the processing continues with entry.

Returns:

I_MapEntry the modified entry.

Throws:

XmlBlasterException - if something goes wrong when making the change (for example if the entry is not in the map) or if the callback throws an exception.

See Also:

I_Map.change(I_MapEntry, I_ChangeCallback)

updateCounters

public void updateCounters(org.xmlBlaster.engine.msgstore.I_MapEntry entry)
                    throws XmlBlasterException

Specified by:

updateCounters in interface org.xmlBlaster.engine.msgstore.I_Map

Parameters:

entry - the entry to change. This is the old entry, i.e. the entry on which the modification has to take place by callback. Or it is the new entry and you can pass null for callback. IMPORTANT: This method is not threadsafe since it does not make a lookup to get the actual entry. The specified entry could be a dirty read, in which case the current entry would be overwritten with this dirty value. If you want to work threadsafe you should invoke change(long, callback). That method makes a lookup within the same synchronization point.

Throws:

XmlBlasterException - if something goes wrong when making the change (for example if the entry is not in the map) or if the callback throws an exception.

See Also:

I_Map.change(I_MapEntry, I_ChangeCallback)

change

public org.xmlBlaster.engine.msgstore.I_MapEntry change(long uniqueId,
                                                        org.xmlBlaster.engine.msgstore.I_ChangeCallback callback)
                                                 throws XmlBlasterException

Description copied from interface: org.xmlBlaster.engine.msgstore.I_Map

This method is threadsafe because it makes a lookup for the updated entry within the synchronization point.

Specified by:

change in interface org.xmlBlaster.engine.msgstore.I_Map

Parameters:

uniqueId - the uniqueId of the entry to change. This is the old entry, i.e. the entry on which the modification has to take place.

callback - the object on which the callback method 'changeEntry' is invoked. The modification of the object is done in that method. If you pass null, then the changeEntry is not invoked and the processing continues with entry.

Returns:

I_Entry the modified entry.

Throws:

XmlBlasterException - if something goes wrong when making the change (for example if the entry is not in the map) or if the callback throws an exception.

See Also:

I_Map.change(long, I_ChangeCallback)

addStorageSizeListener

public void addStorageSizeListener(I_StorageSizeListener listener)

Description copied from interface: I_Storage

Adds a storage size listener to the storage. Every time the number of storage entries changes we will fire a changed() event.

The changed() invocation is guaranteed to NOT be in any Queue specific synchronize

You can use this for example to add a threshold warning system.

Specified by:

addStorageSizeListener in interface I_Storage

Parameters:

listener - the listener to be added, adding the same listener multiple times will only remember one and fire once

See Also:

I_Storage.addStorageSizeListener(I_StorageSizeListener)

removeStorageSizeListener

public void removeStorageSizeListener(I_StorageSizeListener listener)

Description copied from interface: I_Storage

Removes the specified listener from the queue.

Specified by:

removeStorageSizeListener in interface I_Storage

Parameters:

listener - the listener to be removed. Currently only one. If you pass null, all queueSizeListeners are removed.

See Also:

I_Storage.removeStorageSizeListener(I_StorageSizeListener)

hasStorageSizeListener

public boolean hasStorageSizeListener(I_StorageSizeListener listener)

Description copied from interface: I_Storage

Checks wether the specified listener is registered.

Specified by:

hasStorageSizeListener in interface I_Storage

Parameters:

listener - the listener to check against. If you pass null it checks if at least one listener exists.

Returns:

true if the specified listener exists, false otherwise. If you passed null in the argument list it returns true if a listener exists.

See Also:

I_Storage.hasStorageSizeListener(I_StorageSizeListener)

getStorageSizeListeners

public I_StorageSizeListener[] getStorageSizeListeners()

Specified by:

getStorageSizeListeners in interface I_Storage

Returns:

the array of storage size listeners for this storage. It never returns null.

See Also:

I_Storage.getStorageSizeListeners()

embeddedQueueObjectsToXml

public long embeddedQueueObjectsToXml(java.io.OutputStream out,
                                      java.util.Properties props)
                               throws java.lang.Exception

Description copied from interface: I_Queue

NOTE: rename from embeddedObjectsToXml to embeddedQueueObjectsToXml as it used the map lookup and lost priority info Dump all entries of this queue to the given output stream. The messages are XML formatted.

Specified by:

embeddedQueueObjectsToXml in interface I_Queue

Parameters:

out - The output stream to dump the entries

props - Configuration properties, not yet specified, just pass null

Returns:

Number of entries dumped

Throws:

java.lang.Exception

embeddedObjectsToXml

public long embeddedObjectsToXml(java.io.OutputStream out,
                                 java.util.Properties props)
                          throws java.lang.Exception

Note: Is currently implemented assuming I_MapEntry and NOT I_QueueEntry (but I_Queue offers this method which is wrong)

Specified by:

embeddedObjectsToXml in interface org.xmlBlaster.engine.msgstore.I_Map

Parameters:

out - The output stream to dump the entries

props - Configuration properties, not yet specified, just pass null

Returns:

Number of entries dumped

Throws:

java.lang.Exception

See Also:

I_Queue#embeddedObjectsToXml(OutputStream, Properties), I_Map.embeddedObjectsToXml(OutputStream, Properties)